(19)
(11) EP 0 373 293 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.06.1991 Bulletin 1991/24

(43) Date of publication A2:
20.06.1990 Bulletin 1990/25

(21) Application number: 89114133.5

(22) Date of filing: 31.07.1989
(51) International Patent Classification (IPC)5: B29C 45/28
(84) Designated Contracting States:
AT BE CH DE ES FR GB GR IT LI LU NL SE

(30) Priority: 16.12.1988 CA 586166

(71) Applicant: Gellert, Jobst Ulrich
Georgetown Ontario L7G 2X1 (CA)

(72) Inventor:
  • Gellert, Jobst Ulrich
    Georgetown Ontario L7G 2X1 (CA)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Injection molding rack and pinion valve pin actuating mechanism


    (57) A valve gated injection molding system having a double acting pneumatic rack and pinon valve pin actuating mechanism. The melt passage branches in a manifold (14) from a central inlet (12) and flows along the valve pin (28) in a central bore (16) in the nozzle (18) to the gate (20). A pneumatically driven piston (96) pivots a toothed pinion member (84) mounted in a slot (74) in the manifold (14). The pinion member (84) engages a toothed rack member (76) which reciprocates along a straight line in the slot (74) in the manifold and engages an enlarged head (66) of the valve pin (28) in a slot in the rack member (76). Lateral forces from the pinion member (84) are absorbed by sliding contact of surfaces of the rack member (76) against matching surfaces of the slot (74) and/or a valve pin bushing (26), and are not transmitted to the valve pin (28). This avoids uneven wear and buildup of melt deposits around the valve pin which can otherwise result in leakage and malfunction.






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